Electromagnetism defined as “magnetism produced by an electric current”. In other words it is the electricity part of what holds ourselves and every bit of matter in the universe together. This source of universal “glue” is found within atoms themselves.
As the name sounds, there are two different forces within electromagnetism – the electric force and the magnetic force. Before the early part of the last century, scientist studied electricity and magnetism as different sciences. No one knew the connection between them.
Electromagnetism was found almost by accident, that a” flow of electric current (a movement of electrical charge) creates a magnetic force” to use the words of Jack R. White, author of The hidden World of Forces.
I will first explain the magnetic force in electromagnetism. Nearly 900 years ago, the Chinese discovered the natural permanent magnet – lodestone or magnetite. After playing around with this rock they discovered that when floating on a piece of wood it would always point itself north. From this they then created a magnetic compass. To the Chinese in that time, magnetic force seemed to be magic, but in the twentieth century we use magnetic fields everyday. In such things as the refrigerator, the washing machine, the dryer, and the vacuum cleaner all have electric motors.
The magnetic force can be created many different ways but the two main ones are:
Ferromagnetism – “caused by the orientation direction of certain kinds of atoms.
Electromagnetism – “caused by passing an electric current through a conductor such as metal wire”
Both of these magnetic fields, once created, is exactly the same.
Electromagnetic Radiation by definition is “ the transmission of energy in the form of waves having both an electric and a magnetic component”. It is impossible for a wave with just one or the other to exist. The most common forms of electromagnetic radiation are radio waves and light waves.
The Theory of electromagnetic fields was developed by James Clerk Maxwell of Scotland and published in 1865. His work was the first of many other experiments and “theoretical” research that many other well known scientists have used his works with there own experiments. Maxwell presented a set of equations that completely describe the electromagnetic field. How it is produced and charged by currents, and how it is distributed in space and time. Accompanying the electric component is a magnetic component – which are both equal. It may be shown that electromagnetic waves transport energy as well as carry momentum. It way also be shown that “any other accelerated charge, not necessarily a sinusoidal oscillating one, loses energy in the form of electromagnetic waves”